To obtain hydrocarbons, a drilling tool is driven into the ground surface to create a wellbore through which the hydrocarbons are extracted. Typically, a drill string is suspended within the wellbore. The drill string has a drill bit at a lower end of the drill string, and the drill string extends from the surface to the drill bit. The drill string may be formed by drill pipes joined together, a coiled tubing string, casing joined together, and/or combinations thereof.
Wired drill pipe is a type of drill pipe which has a communication channel within each pipe joint. Early approaches to a wired drill string which use wired drill pipe to convey signals are disclosed in U.S. Pat. No. 4,126,848; U.S. Pat. No. 3,957,118; U.S. Pat. No. 3,807,502; and the publication “Four Different Systems Used for MWD,” W. J. McDonald, The Oil and Gas Journal, pages 115-124, Apr. 3, 1978.
Use of inductive couplers to convey signals, such as inductive couplers located at the pipe joints, has also been proposed. The following disclose use of inductive couplers in a drill string: U.S. Pat. No. 4,605,268; Russian Federation published patent application 2140527, filed Dec. 18, 1997; Russian Federation published patent application 2040691, filed Feb. 14, 1992; and PCT Patent Application Publication WO 1990/14497. Also see U.S. Pat. No. 5,052,941; U.S. Pat. No. 4,806,928; U.S. Pat. No. 4,901,069; U.S. Pat. No. 5,531,592; U.S. Pat. No. 5,278,550; and U.S. Pat. No. 5,971,072.
U.S. Pat. Nos. 6,641,434 and 6,866,306 to Boyle et al., both assigned to the assignee of the present application and incorporated by reference in their entirety, disclose a wired drill pipe joint for reliably transmitting measurement data between a surface station and locations in the wellbore in high-data rates and bidirectionally. The '434 patent and the '306 patent disclose a low-loss wired pipe joint in which conductive layers reduce signal energy losses over the length of the drill string by reducing resistive losses and flux losses at each inductive coupler. The wired pipe joint is robust because the presence of gaps in the conductive layer does not prevent operation of the wired pipe joint. These and other advances in the drill string telemetry art provide opportunities for innovation where prior shortcomings of range, speed and data rate were limiting on system performance.
Regardless of the type of drill string used, drilling operations may be conducted in vertical, horizontal or deviated orientations of the wellbore. Vertical drilling refers to drilling in which the trajectory of the drill string is inclined approximately ten degrees or less. Horizontal drilling refers to drilling in which the drill string is approximately perpendicular to the ground surface. Deviated orientations of the wellbore include drilling in which the trajectory of the drill string is inclined with respect to the vertical.
Drilling at greater depths is more common recently, and drilling at greater depths typically results in exposure to higher pressures and temperatures. Downhole temperature and pressure are the two most common limiting factors for the successful utilization of advanced drilling tools. In addition, incomplete understanding of the thermal system negatively impacts formation evaluation in all phases of well construction, production and storage. While subsurface temperature and fluid pressure gradients vary regionally, both temperature and pressure generally increase with depth. Accordingly, the need to operate at higher static temperatures and pressures increases as wellbores are drilled deeper into formations for hydrocarbon and water production, thermal energy extraction, and fluid and gas storage.